T_Y's Build Log

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T_Y
Posts: 153
Joined: Thu Mar 15, 2018 12:51 am
Location: York

Re: T_Y's Build Log

Post by T_Y »

Ant Freeze 7 was technically my most successful event, in that one bot won the most fights in a competition on record for me... at 2 wins 2 losses XD

PM2 went 0/2. The first fight against Unorthodox was fun. That thing has a 70g servo giving its flips so much oomph. Eventually, the gearing slipped, which meant that I couldn't self-right. The second was against Team Effort's cluster, who pitted me with ease. I really need to get some more driving practise in against other people!

Error 404's debut was fun. Although it went 0/2, it proved that the mechanum wheels did work in the arena, as I managed to get around to the side of my opponents on several occasions. However, because it has no pushing power, I couldn't do anything once there. Unfortunately, Error 404's entire group had pushbots and flippers, with only spinner (which was the kind of opponent I'd wanted to fight with Error!), so I was very easily controlled by my opponents.

HYTTIOAOA is my most successful bot in competition, sitting at 2/2. I admit the first win was pretty lucky on my part, when my opponent and I charged at each other, he deflected off my sloped front into the pit. The first loss was against Shows Up and Kills Thanos, so I attached the aluminium wedge... it turns out that when I made it, I left a tiny shard of aluminium sticking out on the right hand side, and this is what caused HYTTIOAOA to veer right when I drove it in AWS 60 and this fight... that very quickly got cut off.

There's a few weeks to RoboDojo's sportsman beetleweight, full comabt antweight and bodgebots event, so I'll only be working on minor tweaks to the three. I really need to fix PM2's gears from slipping. A couple of ideas floated around at Ant Freeze, one was to increase the engagement for the teeth, and to get an aluminium servo horn to eliminate that as a factor in the give in the system.

I'm also toying around with the idea of cramming a second KingMax servo in there...
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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T_Y
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Re: T_Y's Build Log

Post by T_Y »

Small update, the STL files for the mechanum wheels are now available on Thingiverse! https://www.thingiverse.com/thing:4130500

I also might have committed to attempting to make 2 servo PM2 a thing now...

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Thomas - Approximation Robotics AKA "the one that does the mechanums"

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T_Y
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Re: T_Y's Build Log

Post by T_Y »

I came up with a new axe mechanism for Percussive Maintenance the other day, and have been busy building a prototype. It's loosely based on traditional flipper linkages to get a larger range of motion from the axe given the limited servo arm motion.

https://youtu.be/YQyxexTrDvI

It seems to work fine, so I'm going to incorporate it into a new version of Percussive Maintenance.

Introducing Percussive Maintenance 3: Revenge of the Spanner.

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This will probably not be ready in time for Robodojo next week but should be ready before AWS61.
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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Re: T_Y's Build Log

Post by T_Y »

I forgot to update this after Robodojo!

I've uploaded the fights here https://youtu.be/xDOLusqwuQs except for the first fight, it seems I missed it during the export.

There were only 6 of us competing, but that meant we could each get a lot of fights in - everyone had 3 robots, so we did a round robin where you would pit each of your robots against one of your opponents. This meant we got a whopping 15 fights each, before bodgebots and the gladiator!

The night before, I printed off a new gear for PM2, which added a lip to one side of the gear, which seemed to largely resolve the gear slipping issue (at least, until the gladiator). I'm working on version 3 for AWS 61.

HYTTIOAOA won a couple of fights, not much to say here. I think I am getting better at driving bots in general though, I managed to last a while in some of the fights.

I was really interested in Error 404's performance at Robodojo. It's first fight was against Stolen Concept, a horizontal spinner a la Carbide. For the first minute or so, it held up very well, taking the kits to the defensive wedge no problem, and the mechanum wheels really helped me to stay facing it for the most part. However, because the wedge wasn't fixed to the bot (it just rests on two posts that stick out the middle, eventually, the wedge popped off. Aaand...

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Well, that's fine, I brought plenty of spares! I did lose one of the motors, though I think the ESC might still be okay. I entered the second fight without rollers, as I didn't have enough time to get them on, though they returned for the third fight against Dennis.

The fight against Dennis was the only fight of the day to go the distance. I think this was partly due to the larger than normal arena, but I think this fight really demonstrates how mechanum wheels might be useful. For a lot of the engagements, I could keep the scoop facing Dennis, which got under it more often than not. The strafing ability also helped to escape multiple times when Dennis managed to push me towards the pit. The main issue to solve now is traction.

For the bodgebots, I brought an empty filament spool that I hadn't gotten round to disposing of. I hacked off the two sides and shoved the electronics inside the centre, reattached the sides and voila - I have a thwackbot! It fell apart during every fight though, as the wheels weren't attached very well!

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With 2 weeks before AWS 61, I've been working on Percussive Maintenance 3: Revenge of the Spanner. I've spent this weekend making the body, so now all that's left to do is re-wire the guts from PM2 to fit into the new chassis.

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If I have time, I'll see what I can do about Error 404's traction issues.
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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LimaHotel
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Re: T_Y's Build Log

Post by LimaHotel »

Any metal going on there to beef it up / take impacts away from them skinny lookin brittle PLA brackets on the corners? THOMAS Y U DO THIS this isn't even a fancy shape!
A grabber? I CHALLENGE IT WITH JIGGY!
T_Y
Posts: 153
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Location: York

Re: T_Y's Build Log

Post by T_Y »

PLA+! IT'S PLA+!

Joking aside, I'm going to wait and see how much weight I have left over once the electronics go in. I'll either go for 0.5mm Ti or 1mm Alu on the front I think.
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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LimaHotel
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Re: T_Y's Build Log

Post by LimaHotel »

*cough* recycled steel master race *cough*
A grabber? I CHALLENGE IT WITH JIGGY!
T_Y
Posts: 153
Joined: Thu Mar 15, 2018 12:51 am
Location: York

Re: T_Y's Build Log

Post by T_Y »

Percussive Maintenance 3: Revenge of the Spanner is now complete! Video here: https://youtu.be/L7LhTIIfQ04

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The shape of this chassis appears to work better for pushing (the tough hub wheels also help!). Interestingly, the shape has the side effect of allowing me to use the axe like a Sandstorm-style front hinge weapon. Nice! I think the weapon is a bit slower than the gear linkage, but it does reliably self right.

With the extra space in this chassis, I decided to connect everything with dupont and jst connectors, to allow for easier swapping of components. I did mess up a bit doing the wiring, though. I had the drive set up and working, but the weapon wasn't working. It took me 2 hours to realise... I had plugged it in the wrong way round, with Rx signal to servo ground and battery ground to servo signal... oops!

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For horizontal spinners, I made alternate 1mm aluminium front plates, with a lip bent at 90 degrees around the gap for the weapon. The thinking behind that is if a horizontal's tooth gets behind the front plate, it could rip it off. Having the flange there should reduce the bite and hopefully keep the front plate attached.
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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Re: T_Y's Build Log

Post by T_Y »

I've been busy working on a new bot!

I wanted to go back to my front hinge after neglecting it. This time, I opted for a Sandstorm style front hinge. I am calling this new bot Runtime Exception.

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I got this done Sunday and Monday, and had the basic shell cut out by Tuesday.

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Borrowing the electronics from PM3, I hooked up a slightly weaker 6.6kg KingMax to test it out. Aaand...

https://youtu.be/MlNEdkrjeEk

Blimey, that's got some kick to it! Maybe I'll finally have a front hinge capable of throwing bots forward! Now I just need to wait for the electronics to arrive then I can wire up the bot.

You'll notice the angled wheels. There isn't any reason for this except that I wanted to keep the shell shape! What I'll probably do is mount the wheels to a spare bit of plastic to test driving like that first, if I don't like it I'll have to compromise.
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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T_Y
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Re: T_Y's Build Log

Post by T_Y »

The electronics arrived (thanks BBB!), and I have finished Runtime Exception!

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Here it is in action: https://youtu.be/LZlhKOIgR0U

Because the BBB motors are around 700rpm@6V, combined with Shakey's 35mm wheels, it moves quite quickly, and has a good amount of pushing power! The angled wheels aren't that bad, I just needed to trim the aileron and elevator properly to get the motors to turn at the right time.
Thomas - Approximation Robotics AKA "the one that does the mechanums"

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